Nuclear power can generate large quantities of energy without releasing greenhouse gases

It does not depend on the weather

The UK's largest reactor generates the equivalent output of 1188 wind turbines. A nuclear fuel pellet, about half an inch long, provides the same amount of electricity as one and a half tonnes of coal

Spent fuel from nuclear power plants remains toxic for centuries and there is no safe permanent storage facility for it

Dismantling old reactors safely is highly expensive

Mining and enriching uranium also produces toxic waste

Uranium is a finite resource, although there are ways of recycling spent fuel

Fears of nuclear material stolen from power facilities being used by terrorists in a so-called "dirty bomb" have increased since the 11 September attacks

Nuclear power is currently generated from nuclear fission - splitting the nuclei of atoms. Nuclear fusion - combining atomic nuclei - is potentially cleaner because the fuels involved are different. But scientists have been trying to harness the energy from fusion for decades and some say a working fusion generator is still a lifetime away.

There is a close link between civil and military uses of nuclear power